Mayor Kimberley L. Driscoll is expected to be elected president of the Massachusetts Mayors’ Association at the group’s annual meeting on Saturday. The association’s nominating committee voted Dec. 7 to name Driscoll to the one-year, unpaid position; she served as its first vice president last year. Driscoll, who is halfway through her second four-year term as mayor, said recently she looks forward to her new leadership role with the mayors’ group. “It’s a great opportunity to work with other municipal leaders and hopefully bring collective strategies to tackle some of the issues that have been plaguing cities and towns,’’ she said.